This invention relates to improvements in devices for quick freezing of articles such as food products or the like as well as to systems for heating such articles. More particularly, this invention is an improvement to the system described in my prior U.S. Pat. No. 3,688,518 issued Sept. 5, 1972 for a Refrigerated Conveyor System which discloses a device for quick-freezing of raw or cooked foods. The device includes an insulated heightwise extending freezing chimney having an inlet at its upper end and an outlet at its lower end. Trays containing the articles to be frozen are introduced into the inlet at the top of the chimney and are stacked one atop the other vertically within the chimney. The stack of trays is advanced downwardly in incremental steps by a drive mechanism. The trays are designed so that when stacked, their contained articles will be exposed to a cryogenic coolant which is sprayed across the articles in the trays. The internal surfaces of the chimney are provided with deflectors which cooperate with the stacked trays so that when the stack is advanced downwardly in incremental steps, the flow of coolant will be reversed over and in relation to each tray. Thus, the coolant flows upwardly and along a transverse zigzag path to achieve maximum cooling effect along the height of the chimney.
In the machine described in my prior patent, means are provided for automatically withdrawing the lowermost tray from the stack and for transporting that tray away from the machine. The mechanism also serves to advance the stack incrementally and automatically downwardly to its next lower incremental position in the machine. The machine described in my foregoing U.S. patent, having the automatic withdrawal and advancing apparatus may, in a number of instances, have too large a capacity for some environments. For example, in a relatively small restaurant, an automated conveyor system, because of its necessarily larger capacity, would necessarily be idle much of the time. The present invention relates to an improved system which is better suited for use in smaller environments having reduced capacity requirements.